Update proposal README

Fixes a typo and adds a link to the rendered spec.

Author: takikawa

README.md

@@ -4,7 +4,9 @@
 
 This repository is a clone of github.com/WebAssembly/spec/. It is meant for discussion, prototype specification and implementation of a proposal to add ES module integration to WebAssembly.
 
-The [specifics of the ES Module integration Propsal are found in this subfolder](/proposals/esm-integration).
+The [specifics of the ES Module integration Proposal are found in this subfolder](/proposals/esm-integration).
+
+A formatted version of the spec, including this proposal, is available here: webassembly.github.io/esm-integration.
 
 Original README from upstream repository follows...